Jack



May 1927' w. a. TEMPLETON JACK Filed April 5, 1922 Patented May 3, 1927.

UNITED STATES PATENT OFFICE.

This invention relates to improvements in lifting jacks, and has reference more particularly to an improved structure of jack base.

The maximum productiveness and safety ofany lifting jack depend largely upon its ground bearing or foundation. Owing to the heavy loads which jacks are required to carry, it has long been customary to form the casing or standard of the jack with a base of substantial area and taperingor less period of use the edges of thebase,

and particularly the front side edges, tend to bend or curl upwardly thus giving a more or less rounded or convex form to the bottom. This, in turn, has a tendency to cause the jack to kick out from under its load, especiall where the latter is carried by the 'forwar 1y projecting foot of the lift ing-bar or a. similar attachment ofthe lifting-bar.

In an. effort to overcome this bending of the edges of the jack base many jacks have been built with extra heavy bases thicker than any other portion of the standard. or frame, but this uneven distribution of the metal produces weakness through checks or strains in the casting, during its cooling or annealing; and efforts to straighten these heavy bent bases usually produce fractures or failures.

The main object of the present invention is to provide an impror ed jack base which shall be free from the faults above enumerated, and especially the tendency to bend or curl upwardly at the edges which, as stated, renders the jack unsafe and unreliable. In carrying out my invention I re tain substantially the standard size and form of jack base now extensively used but, in lieu of making it as a solid casting, I make it a hollow structure and I preferably form in the bottom wall of the base a substantially central slot; as a result of which, the bottom Wall, instead of tending to assume a more or less convex shape under wear, tends gradually to assume a more or less concave shape with repeated use, thereby insuring that the edges shall always be in firm contact with the ground or other founratcheted lifting-bar 7.

WALTER IB; TEMPLETON, OF CHICAGO, ILLINOIS.

JAGK.

3& Application filed April 5, 1922. Serial No. 549,710.

dation and effectively preventing any slipping or kicking out from under the load.

My invention, its novel structural features, and mechanical advantages will be apparent to persons skilled in the art froln the following detailed description, when taken in connection with the accompanying drawing in which I have illustrated one practical and approved embodiment of the invention, and in which Fig. l is aside elevation of the lower portion of. a jack casing and its base, i11- cluding the foot of the usual lifting-bar;

Fig. 2 is a horionztal section on theline 22 of Fig. 1, showing the base in top plan;

Fig. 3 is a rear elevation, partly broken out;

Fig. 5 is a bottom planview ona reduced scale.

Referring to the drawing, 6 designates the hollow vertical casing of alifting jack within which is slidably mounted and guided the The front wall of the casing 6 is vertically. slotted, as usual, and through this slot extends a forwardly projecting foot 8 of the lifting-bar, said foot being formed with vertical grooves 9v on either side that. are slidingly. engaged with the spaced margins 6 of the front wall of the casing that constitute the vertical edges of the slot. Integral with the rear wall of the casin 6 is the usual central stiffening rib 10, of T-form in cross section, which merges at its lowerend into the base.

The base, instead of being a solid casing as heretofore, is hollow and, in the form shown, comprises a Hat bottom wall 11, a downwardly and forwardly inclined front. wall 12, a somewhat steeper downwardly and rearwardly inclined rear wall 13, and downwardly and outwardly inclined side walls 14, all of said walls merging at their lower edges into the outer edges of the bot tom wall 11 and at their upper edges into the lower portion of the casing 6. It will be observed by reference to Figs. 3 and 4c that the bottom wall 11 is of gradually decreasing thickness from its outer to its inner ed es.

Increased stiffness and strength to resist vertical stresses are secured by the provision of a pair of opposedinternal. vertical ribs 15 (Fig. 3) extending between the bottom wall 11 and the side walls ll and front wall 12.

In the front wall 12 is formed the usual rectangular slot 16 which accommodates the passage of the foot 8 of the lifting-bar; and in the bottom wall or plate 11 of the base beneath and in register with the slot 16 and preferably extending from the vertical plane of the forward end of the slot 16 to a point in or slightly behind the vertical plane of the rear wall of the casing 6 is a rectangular oblong slot 17 which, it will be observed, occupies a sul'istantially central area of the base. Fo all purposes of the present invention this base slot is not essential; but it is preferably employed for the reason that continued use and pressure upon the base give the latter a permanent concave set which causes the margins of the base to grip the foundation or support, thus preventing any possible tilting, rocking or kicking out from the load. Where the jack is employed as a track jack this construction also prevents the throwing of the track or rail out of alignment through lateral thrust. The improve ment is also useful and advantageous in practically all other types of jacks such as those used in mining, pole pulling, wrecking operations and for automobiles and motor trucks, and especially in jacks equipped with a lifting foot or like element that lies partially or wholly at one side of the central vertiral axis of the base.

Obviously the coring or hollowing of the base lightens rather than increases the weight, and gives to the bottom wall the structure and character of a comparatively thin section, that, being malleable, conforms to the line of pressure and, with use, forms a concaved base, which transmits to its rim the burden of the load, somewhat after the fashion of an inverted saucer. This tendency of the base wall to assume a slightly concave form under the heavy loads transmitted thereto is caused in partby the presence of the central opening or slot 17 and in part by the gradually decreasing thickness of the wall between its outer margins and its center. Irrespective of these features, howherein shown one practical en'ibodiment of my invention for purposes of illustration; but manifestly the form and details thereof may be varied within the scope and pin-view of the appended claims without involving any departure from the principle of the invention or sacrificing any of its merits and advantages.

I claim:

1. A casingfor a lifting jack adapted to support eccentrically applied loads, said casing formed with a hollow malleable cast metal base comprising outwardly and downwardly flaring front, rear and side walls, and a substantially fiat bottom wall integrally joined to and extending inwardly of the lower margins of said walls, said bottom wall being of grzidually decreasing thickness from its margins to its center, whereby it tends to assume an inverted dish shape under heavy loads.

2. A casing for a lifting jack adapted to support ecce'ntrically applied loads said rasing formed with a hollow malleable cast m etal base comprising outwardly and downwardly flaring front, rear and side walls, and a substantially flat bottom wall integrally joined to and extending inwardly of the lower margins of said walls, said bottom wall having a central opening and being of gradually decreasing thickness from its outer margins to the said opening, whereby it tends to assume an inverted dish shape under heavy loads. 

